The W.M. Keck Biomedical Mass Spectrometry Lab is dedicated to providing access to state of the art mass Spectrometry instrumentation and highly trained personnel. The facility currently has a time-of-flight mass spectrometer (ABI Voyager DE-Pro) equipped with a MALDI source (MALDI-TOF) for high accuracy mass measurement of peptides and small molecules as well as detection of intact proteins up to ~150 kDa. In addition, one ion trap and one hybrid ion trap-FTICR each equipped with microspray sources (Thermo Electron LCQ DecaXP and LTQ-FT) provide detailed information on proteins such as identification, relative quantitation, and post-translational modification discovery. In particular, the FTICR is capable of high resolution/mass accuracy at ultra-high sensitivity. For larger numbers of samples, the facility has 96-well format automated equipment such as the Genomic Solutions ProGest (sample digestion) and the Genomic Solutions ProMS (sample processing for peptide mass fingerprinting). The critical mission of the facility is to provide Cancer Center investigators with expertise in pre-experiment planning, data acquisition, and data interpretation for a wide variety of experimental questions ranging from basic science to clinical applications. This 'start to finish'guidance provides investigators with interactions critical to experimental success and is not often found at other facilities. Lab personnel also give periodic lectures to the university community to keep investigators apprized of currently available instrumentation and techniques and to keep themselves current on the types of questions Cancer Center members would like to address in their research.